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Json – Connect to API fails with C#

I have tried various C# codes approaches for connecting to an API but cannot so far get it to work. The URL works every time with a Chrome browser. I have looked at many post here on Stack Overflow but have not found answers the problem.

In C# I have tried webclient, httpclient, no luck. With postman I get the data easily. I have tried to watch the request with Fiddler 4. The postman request works great and is easy to see but when running the C# code the request never shows up despite https traffic gets captured and decoded. Many times it is timeout or connecting was closed. I do not believe it to be a firewall issue. Here is some C# that does not work:

internal class Program
{
    static void Main(string[] args)
    {
        Getit();
    }

    private static async void Getit()
    {
        try
        {
            string baseUrl = "https://api.nasdaq.com/api/nordic/instruments/CSE32679/trades?type=INTRADAY&assetClass=SHARES&lang=en";
                            
            var client = new System.Net.Http.HttpClient();
            //var request = new System.Net.Http.HttpRequestMessage(System.Net.Http.HttpMethod.Get, baseUrl);

            var request = new HttpRequestMessage
            {
                Method = HttpMethod.Get,
                RequestUri = new Uri(baseUrl),
                Headers = {
                { HttpRequestHeader.UserAgent.ToString(), "Could try to set this" },
                { HttpRequestHeader.Accept.ToString(), "application/json" },
                { HttpRequestHeader.Cookie.ToString(), "ak_bmsc=057AA34F94542D7FBF06A239807E1BC8~000000000000000000000000000000~YAAQHmjdWE1nYjiTAQAASfEPZRmj3xtTz7eQGDtn2GEgSGhkx070psq3nqpvIhA3wzaXGJm2o91q1M3D6DvQwqUZzuw+esKY13f8GdqUt4dJPxrgvfliIS8ehkC7YBSn7IH6Bcw/8s8hOjaP8i3WszFF0UMpQ4EaBthZep9yFYRYELgRMKXnMyzQBUsdAPhaoZIB9An1hH3LmRhIIx9zkwRt4TCY3O2eBOYzaHyo95pTmhp9SSWzHUM6RCj5+owjXtoHDlSjIHRmCVwtpNp20gn5b70Dvvb4C6tpdNUWvK8YJFbs6M5h+0ho0Z0SfGND59oPOaMSA5/i8wRKfiV/fl7ZtQtyQ8RQDxcMxA==; akaalb_ALB_Default=~op=ao_api_port_8085:ao_api_east2|~rv=23~m=ao_api_east2:0|~os=ff51b6e767de05e2054c5c99e232919a~id=ad3d95899a893885df1dfabdf47494ac" },
                { "X-Version", "1" }
                    },
                
            };

            var response = await client.SendAsync(request);
            response.EnsureSuccessStatusCode();
            Console.WriteLine(response.Content.ReadAsStringAsync());

        }
        catch (Exception e)
        {

        }
    }      
}

Can someone help me by showing some C# code that will do it?

Tags:

2

Answers


  1. 0

    You’re going to kick yourself.

    You need an await statement in front of response.Content.ReadAsStringAsync()

    The entry for the User Agent header – not sure about the .ToString() approach, but verbatim the key needs to be "User-Agent" with a dash.

    Other than that, download Fiddler Classic to view your web traffic. It’s the best! https://www.telerik.com/fiddler

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  2. 0

    Your Getit() is async but your Main isn’t. That means, when calling Getit() the control flow Returns to Main when the first await is encountered. And as there is nothing else to do in Main the program exits. The .net runtime does not wait for still running async tasks.

    Depending on your version of .net the simplest solution is to make your Main also async and put an await wherever you need one.

    ...

public static aync Task Main() {
   await Getit();
}

...

    Furthermore it’s bad practice to return void from an async method, because then you can’t await it. Return a Task instead

    private static aync Task Getit() {
  ...
}

    And finally, you have also to await the ReadStringAsAsync

    Console.WriteLine(await response.Content.ReadAsStringAsync())
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